Abstract
In “inattentional blindness”, attention is assumed to be the necessary factor in gating access to conscious awareness, while expectations are only thought to be important because they affect the allocation of attention. In four experiments (N=763), we challenged this assumption and examined the unique role of expectations in the detection of attended objects. We present evidence for a new phenomenon we term “expectation-induced blindness” (EIB). Participants were presented with rapid serial visual presentation (RSVP) streams and had to identify an alphanumeric character (letter or digit) indicated by a cue. The target category repeated for 19 trials and then unexpectedly switched from the 20th trial onward. In all experiments, accuracy was reduced on the surprise trial when the category switched and returned to baseline levels on the following trial. In Experiments 2-4, no drop in accuracy was observed when the target changed from one subset of possible targets to another subset from the same category, ruling out item novelty ss the critical factor for EIB. In Experiment 3, this pattern emerged even when the pre-cue appeared prior to the target, indicating that EIB cannot be attributed to changes in attentional guidance alone. Experiment 4 demonstrated that expectation induced blindness is also elicited for real-world photographs of visual objects (human and animal faces). These findings show that the awareness of visual objects is gated by predictions. When expectations about object categories are wrong, observers often fail to notice objects even though they are task-relevant and in the focus of attention. EIB may be linked to expectation-induced activations of long-term memory representations, resulting in encoding benefits for expected and costs for unexpected objects.